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California Officials Tackle a Toothy Lake Predator

California is redoubling its efforts to rid Lake Davis of the northern pike.Credit
Jim Wilson/The New York Times

PORTOLA, Calif., Sept. 11 — The poison didn’t work, and neither did the hook and bobber. The electrical probes were somewhat effective, but don’t even ask about the explosives.

For the last decade, the state of California has waged a Sisyphean battle against the northern pike, a fish and a voracious eating machine. In the mid-1990s, when pike were first found in Lake Davis, a Sierra Nevada reservoir about four miles north of here, the discovery set off a panic over the potential impact on the local trout-fishing and tourist industries as well as the possibility of the fish migrating to fragile ecosystems downstream. Since then, millions of dollars and thousands of man-hours have been spent trying to spike the pike.

But while the methods, including poison, electro-fishing, explosives and decidedly low-tech nets, have varied, the results have remained the same.

“We’ve taken 65,000 pike out of the lake,” said Steve Martarano, a spokesman for the State Department of Fish and Game. “And we haven’t made a dent.”

But like Captain Ahab or perhaps Wile E. Coyote, the state has not let a little adversity stop it. On Monday, more than 500 fish and game personnel began a last-ditch, $16 million effort to rid the lake of pike, the most expensive ever undertaken against an “invasive species” in California. “This is a top-of-the-line predator,” said Ed Pert, the project manager. “If we don’t get it this time, we may need to rethink things.”

The lake was closed after Labor Day to prepare for the watery assault. The plan is simple: poison the fish with 17,000 gallons of rotenone, a commonly used pesticide that is absorbed through the gills and blocks the ability to process oxygen. Rotenone is widely considered safe for mammals and other nongilled animals, though some concerns have been raised about links to Parkinson’s disease and some types of cancer.

But Gerald Sipe, the director of environmental health for the Plumas County Public Health Agency, said his office had determined that the treatment plan would not adversely affect the public.

It is not the first time the state has used rotenone in Lake Davis. In 1997, officials used a powdered form of the poison, which fouled the lake, Portola’s longtime water supply. (The town now primarily draws its water from wells.) The state later approved a $9.2 million settlement with the city and the county for businesses, homeowners and local residents. And, two years later, the pike were back.

This time, though, the state is using a milky liquid version of rotenone, and is focusing on the streams and tributaries that lead into Lake Davis, a 4,000-acre artificial reservoir about 60 miles north of Lake Tahoe. On Monday, about 60 workers staffed “drip stations” in creeks and streams while others sprayed ponds and other still waters with poison from plastic backpack tanks.

The state has also begun an extensive education effort. On Monday, two dozen reporters and television crews crowded around a rocky streambed as Stafford Lehr, a fishery biologist, described his pike-killing method.

“These fish will be exposed to the product for eight hours,” said Mr. Lehr, who wore a cowboy hat, goggles and white coveralls. “Which is more than enough time to kill these individuals.”

No one knows exactly how many of “these individuals” live in Lake Davis, though estimates run anywhere from the tens of thousands to the hundreds of thousands. Nor does anyone know where the pike came from, though Mr. Martarano says they may have been introduced by sport fishermen who prize its fight or even “eco-terrorists” who might have introduced the pike “just to cause trouble.”

Whatever the cause, the pike is not a friendly newcomer to any ecosystem. A slender, razor-toothed hunter that can grow to more than three feet long, the pike has been known to devour anything it can get its pointed maw around, including frogs, waterfowl and — legend has it — small dogs.

Photo

In support of the states eradication effort, residents in the Lake Davis area recently burned a 13-foot-long effigy of the pesky northern pike, made of papier-mâché with nails for teeth.Credit
Sara Bensinger

While not a flashy menu topper like tilapia or trout, pike is edible, even glorified by some palates, though its bones make for challenging chewing. But in California, it is illegal to possess, dead or alive, Mr. Martarano said.

State officials are particularly concerned that the pike might escape to the Sacramento-San Joaquin Delta, where it could feast on other fish, including valuable salmon and threatened species like the delta smelt. Signs on the lake recommend cutting the head off any pike caught and tossing the fish back in the water, apparently to show the other pike that human beings mean business.

On Monday, at least, the poison seemed to be working. Within a few hours, fingerlings were starting to turn belly-up downstream, with reports on Tuesday of bigger pike giving up the ghost. The body of the lake will be treated in late September.

After the poisoning is complete — and all the dead fish are scooped out of the water — the lake will be tested for toxicity, and will remain closed for two months, Mr. Martarano said. After that, restocking will begin, with a goal of one million trout in Lake Davis by 2010.

Not every effort has been as encouraging. In March 2003, the department used underwater detonation cord to try to blow up the pike. A grand total of four pike were killed. Jim Murphy, the city manager in Portola, a railroad town of 2,300 people along the Feather River, said he was guardedly optimistic about the new plans. “I don’t think any of us want or encourage a chemical being put in our drinking water or our recreational lake,” he said. “But we better understand the issues and need now.”

That sentiment was echoed by Sara Bensinger, who runs the Grizzly Country Store, a fishing tackle and potato chip outlet on the lake’s southern shore. Ms. Bensinger said her business had been badly hurt by the pike problem, and the bad press that followed. On Sept. 1, she and about 200 other locals gathered to celebrate the beginning of the eradication effort by burning of a 13-foot-long papier-mâché pike, complete with nails for teeth.

“They’re going to get it right this time,” she said. “And then we’re going to start over.”

A version of this article appears in print on , on page A14 of the New York edition with the headline: California Officials Tackle a Toothy Lake Predator. Order Reprints|Today's Paper|Subscribe